Nationality: United StatesExecutive summary: Anti-Terrorism expert, died in 9/11

Around 1995 O'Neill began investigating terrorism, spending considerable effort investigating Al Qaeda and trying to catch Osama bin Laden. He headed the investigation of the USS Cole bombing. He retired from the FBI in July 2001 in some frustration. According to a Frontline documentary "The Man Who Knew", he received interference from Thomas J. Pickard and also from the US State Department, who did not want him investigating Saudi Arabia. After the FBI O'Neill took a job as head of security at the World Trade Center. About one month into his new position he was killed in the collapse of the towers.